Self laying track for tractors



July 3, 1934- F. H. LAMB ET AL SELF LAYING TRACK FOR TRACTORS 5Sheets-Sheet 1 Filed March 28, 1952 ATTORNEY July 3, 1934.

F. H. LAMB El AL SELF LAYING TRACK FOR TRACTORS Filed March 28, 1932 3Sheets-Sheet 2 9- 'drv ATTORNEY y F. H. LAMB l-rr AL SELF LAYING TRACKFOR TRACTORS 1932 3 Sheets-Sheet 3 Filed March 28 ATTORNEY Patented July3, 1934 PATENT OFFICE saumma TRACK FOR 'raaoroas Frank H. Lamb andGeorge E. Lamb, Hoquiam, Wash.

Application March 28. 1932, Serial No. 601,696 1 Claims. (01,. 305- Thisinvention-relates to tractors of the track laying type, and it hasreference in particular to a flexible, self-laying track constructionfor tractors, trailers and the like.

.I The principal objects of this invention reside in the construction ofa track for tractors, trailers,

trucks and other vehicles, comprising a continuous belt made up ofclosely disposed, one piece, reversible track shoes functionally joinedtogether 10 by a plurality of wire strand ropes, or cables,

which extend lengthwise of the track and transversely of the shoes, eachof said shoes being formed with transversely directed, cable channels inits outer face and with sockets co-axial of the channels and the cablesbeing provided, at definite intervals therealong, with ferrules forpivotally seating in the shoe sockets, thereby to definitely space theshoes aswell as to secure them functionally in place with respect toeach other and against slippage on the cables.

Other objects of the invention reside in the details of construction ofthe shoe, especially with respect to the formation of the cable channelsand sockets, to avoid wear on the cables and in the details of andmethod of securing the ferrules on the cables so that when the shoes areassembled therewith, the latter will have maximum freedom of movementwithout wear on the cables, but will be held positively against slippagelongitudinally so of the cables.

Another object is to provide a track requiring minimum means forretaining shoes and cables functionally assembled, and whereincentrifugal force in the moving track will operate to more as securelyanchor the shoes to the cables.

Other objects of the invention reside in the details of construction ofthe various parts, in their combination and in theirmode of use as willhereinafter be more fully described.

In accomplishing these objects of the invention,

we have provided the improved details of construction, the preferredforms of which are illustrated in the accompanying drawings, wherein-Fig. 1 is a side elevation of a part of a tractor having a trackconstructed in accordance with the present invention.

Fig. 2 is an outer plan view, enlarged for better illustration of a partof the track showing the special shoe in which the cable ends areanchored.

Fig. 3 is an enlarged, longitudinal edge view f one of the shoes, partlyin section.

Fig. 4 is a cross section on line 4-4 in Fig. 3.

Fig. 5 is a cross section on line 5-5 in Fig. 3. F18- 6 is a side viewof one of the shoes, and

showing in dotted lines, the rim portion of a driving wheel about whichthe belt travels.

Fig. 7 is an enlarged, sectional view of a portion of track cable.

Fig. 8 illustrates use of short cable lengths in a on track in lieu ofthe continuous cables.

Fig. 9 is a sectional detail showinguse of a cover plate on a shoe toprotect the cables from road abrasion.

hFig. 10 is an enlarged face view of a part of one 55 s cc. shFig. 11 isa similar view of a part of an anchor 12 is a sectional view on line12-12 in Fig. 13 is a side view of a shoe embodying an alternative meansfor retaining the cable ferrules seated.

Track belts of the present type, as used on tractors, trucks, trailersand the like, are usually mounted by a track frame which carries spacedwheels so arranged that the lower run of the belt between the wheels hastractional and supporting contact with the ground. In the event thatthere is considerable distance between the belt mounting wheels, thenguides, idler wheels or other means is provided for holding the trackproperly in place against lateral displacement. If the track is driven,as in the case of its use with a tractor, power is generally appliedthereto through one of the ,mounting wheels. It is to be understood,however, that it is the intention that the present application shallapply principally to the track construction, irrespective of the type ofvehicle it is used on or the manner in which it is mounted or driven.

Referring more in detail to the drawings- In Fig. 1 there is shown apartial side elevation of a tractor equipped with a self laying trackembodied by the present invention. The track, designated in its entiretyby reference numeral 1, when assembled functionally on the track frame,is of continuous belt form and is extended about spaced mounting wheels2 and 3 which have rim portions of channel form, as at 30-13:; 100 inFig. 6. In this instance the wheel 2 has sprocket teeth 4 adapted tocooperate with lugs provided on the ends of the track shoes, aspresently described in detail, to positively drive the track belt whenthe wheel 2 is driven The track belt is made up of transversely disposedtraction shoes 5 all of the same size and all of the same constructionwith the exception of the shoes within which the cable ends areanchored, as presently described, and when asspaced soas to avoid anyinterference one with the other incident to travel of the track and togive additional traction to the belt. The shoes are functionally securedtogether in continuous belt like relation by a plurality of wire strandropes or cables 6 which extend preferably in parallel relationlengthwise of the track and in symmetrical relation relative to thecentral line of the belt.

Each shoe of the track consists of a one piece casting of rectangularform, provided at its opposite ends with thesymmetrically disposedsprocket lugs 7 adapted to engage between the sprocket teeth 4'of wheel2 to drive the belt. On the inner face of each shoe, near its ends, andat the center if desired, tapered lugs 8 are formed and these are solocated as to co-act with .alined idler wheels 9 which are mountedwithin the track frame structure 10, thus to retain the lower rim of thebelt in tractional contact with the ground surface and to prevent anylateral displacement of the track from the frame. In some instances itmay be desired to use these lugs as the driving means for the belt byarranging for them to engage with sockets in the driven wheel. When soused, the special lugs '7 might be eliminated.

The idler wheels 9 as track guiding means, are arranged in two or moreparallel rows and with the wheels in one row overlapping those ofanother. The lugs 8 pass between these two rows of idlers and at alltimes are in contact with a wheel of one of the other row so that nolateral displacement of the track is possible. Also, it is preferredthat the idler wheels have rubber tired treads, as at 9a which willengage flatly with the inner surfaces of the shoes outside and betweenthe lugs 8. Also, the rims 9b of these wheels, as seen in dotted linesin-Fig. 3, which mount the rubber tires, shall project beyond the sidesurfaces of the tire to engage with the guide lugs 8, thereby to protectthe tire against abrasion incident to rubbing contact with the lugs.

In the preferred arrangement, the several cables or ropes 6 which jointhe shoes together are arranged in pairs. In the present instance threepairs are shown and they are symmetrically disposed with respect to thecentral longitudinal line of the belt. It is to be understood, however,that the number of cables employed is optional, as this would depend toa great extent upon the width of track, its use or requirements and alsoupon the strength of the particular cables employed. In some instancesit may be preferred to employ but one cable, or one pair. In otherinstances it may be desirable and practical to use two or more pairs.

When three pairs of cables are used, as in the present instance, each ofthe track shoes is provided on its outer, or what may be termed thetraction face, near its opposite ends and also medially thereof, withspaced, transversely extended cable guide channels 12 within which thecables 6 are individually disposed. These channels are in pairs and eachpair is formed by spaced apart flanges 13-13 cast integral with the shoeplate and transversely thereof and between each pair of flanges a rib14, also integral with the shoe plate, is located so as to divide thespace between the flanges into two channels of equal dimensions. Theinner faces 13a. of the flanges 1313 and also the opposite side faces14a of the rib 14 are arcuately curved, as seen best in Fig. 2, so thatthe paired channels gradually ,sembled on the cables, the shoes areslightly widen out in opposite directions from the medial line of theshoe. Also, the bottom surface 13b of each channel is arcuately curveddownwardly from the medial line in opposite directions; so that thecables will have a desired freedom of movement without any directcontact with the shoes.

Each cable is provided, at equally spaced interval with ferruledenlargements 20. These enlargements are designed to seat pivotallywithin sockets 21 provided therefor in the shoes; the sockets beinglocated in the medial line of the shoe and symmetrically within thechannels. The ferrules, which fit loosely in the sockets, are ofcylindrical form with opposite end surfaces spherically roundedoutwardly and the sockets are shaped accordingly and retain the ferrulesin a sort of ball and socket manner which permits of a very desirableflexibility in the track construction without possibility of slippage ofany shoe on the cables. Also, the form and relationship of the socketsto the channels is such that the ferrules, when seated in the socketsare self centering and support the cables free of the side and bottomsurfaces of the shoe channels and thus wear on the shoes,

as well as on the cables, is eliminated from this cause.

The ferrules are of such diameter as to provide suflicient end surfacethat any unusual wear thereon, or on the ends of the sockets, isavoided. Also, it will be observed by reference to Fig. 10 that the endsurfaces 21a of the sockets 21 are spherically curved to permit of thedesired pivotal movement of the ends of the ferrules, and also thebottom surface, as at 21b in Fig. 4, is accurately curved so that thecylindrical ferrule may rock lengthwise thereon.

It is apparent also that by the provision of the arcuately curvedsurfaces of the channels in which the cables are contained, and the balland socket action of the ferrules in their sockets, there will be acertain freedom of movement of the cable that will permit flexinglaterally or inwardly relative to the shoes without possibility ofkinking or bending as would be the result should the ferrules be rigidlyheld and the cables bent or flexed laterally across a sharp corner. Thepresent design permits the cables to be flexed evenly and without anyabruptness and to rest against the rounded base surfaces of the guidechannels as the shoes pass about the supporting wheels. Also, when thetrack is passing across the ground run, should two adjacent shoes bedisplaced upwardly in ridge like relation, or in an inverted V relation,the character of the retaining channels and freedom of the ferruledportions permits the cables to bend evenly and without any damagingabruptness. Since the cable connections on the shoes are on the outsideof the shoes, and the cables are on the outside of the shoes in thecompleted track, the normal action of the shoes, by reason ofcentrifugal force, is to hold the shoes all the more securely to thecables. Also under tension, as in use, the cables hold the ferrules allthe more securely within their seats.

.While freedom of movement of the shoes relative to the cables ispermitted, by reason of the special design of flanges and ferrules, thismovement is limited to motion at right angles to the longitudinal axesof the shoe.

A novel feature of this track construction resides in the outward orlateral offsetting of the ferrule sockets from the guide channels. Thisdetail provides for the automatic retention of the ferrules in theirsockets so long as the cables are taut. This will be apparent from thecross sectional view of Fig. 3, which shows the overhanging flanges at22 which retain the ferrules in their sockets It has been found byexperiment that under ordinary working conditions, retaining or lockingmeans is not actually required but it is desirable that some holdingmeans, later described, be used as a safety factor to prevent anypossibility of the ferrules becoming unseated by lateral pressureexerted against the cables. It is to be understood, however, thatwithout the holding means in place, an easy detachment of the shoe fromthe cables is possible simply by slackening tension on the cables sothat by bending them laterally toward each other, a slight distance, theferrules may be unseated and the shoe dropped therefrom a The holdingmeans here used consists of bolts 23, that are projected through theshoes between the paired ferrules. Each bolt at its outer end has a head2.4 with side surfaces overlying and conforming in shape to the adjacentsurfaces of the ferrules, and cooperating with the flanges 22 to retainthe ferrules seated. The outer ends of the bolts extend into passages 25in the lugs 8 and have retaining nuts applied thereto to hold them inplace.

It is preferred in this form of track to secure the ferrules in place onthe cables by pressure rolling. The ferrules, in the form of sleeves,are slipped onto the cables then they are properly spaced and rolledunder great pressure so that they are mashed onto the cables; the finalresult being that the ferrules are practically integral with the cables.This method of attachment avoids placing any more holding strain on anyone strand of the cable than on any other and pull on the cable may beapplied through the ferrule to substantially the full strength of thecable.

The cables 6, preparatory to their use in one form of construction ofthe track, are cut in lengths corresponding to the circumference of thetrack. The ends of the cables are not joined but ferrules are appliedthereto flush with the ends. One of the track shoes is designedespecially as an anchor shoe to receive these end ferrules. Such a shoeis designated at 50. in Figs. 1 and 2. This particular shoe ispractically the same in the arrangement of flanges and ribs as any ofthe other shoes, but the ferrule receiving sockets 21' therein providedare of a length sufficient to accommodate the two cable end fer-.

rules in end to end relation and with suiiicient space between theirends for the insertion of a key or looking bolt 26. It will be notedalso that while the side surfaces 218 of these particular sockets arepractically straight up and down so as not to restrict the entrance tothe sockets, the ends of the sockets are counter sunk as at 21C toreceive the base ends of the ferrules which are held againstdisplacement by insertion of thelocking key or bolt 26. This bolt has aflattened head 26a adapted to fit between the ends of the ferrules andit has a shank 26b extended through the shoe and held in place by a nut27 threaded thereonto.

Fig. 3 shows the end sections of the longitudinal ribs rounded or curvedtoward their ends so that considering the shoe from end to end, it is ofrocker form when in contact with the ground surface and this has thespecial advantage that it provides for easier turning of the tractorincident to driving the track at one side at a speed differeat from thatat the other side. These flanges e,- give added strength to the shoeand, with the additional several flanges 13 and ribs 14. which preventlateral slinimge on grades, and give ample traction. so that additionalgrouser cleats are not. required. Furthermore, the surface areaof theseflanges is quite sumcient and so distributed that they will not underordinary travel out into or damage a roadway or pavement on which theyoperate.

It is also observed that the inner faces'of the shoes provide, betweenthe lugs 8, flat bearing surfaces or considerable width for bearingagainst the tires of the idler wheels which maybe of width correspondingthereto so as to reduce to a maximum degree the wear on these parts..

In Fig. 9, is illustrated in cross section an alternative constructionillustrating means for the protection of the cables and ferrules againstroad abrasion should such means be desired. In'this arrangement, aplate, or plates, 40, are secured to the flanges across the socketedchannels and are held by anchor bolts 41. These plates are sufficientlyspaced from the ferrules and cables so as not to interfere with theirfreedom of movement. This protection is useful and desirable where workis carried on in rocky surfaces, or where sharp objects and roadabrasion are damaging to the cables.

In Fig. 13 we have shown an alternative means for retaining the ferrulesseated in the shoe sockets. In this type of construction the sockets arenot undercut but open directly outward. A clamp plate 30 overlies pairedferrules and this is fastened in place by a bolt 31 which extendsdownwardly through the plate and shoe as shown; the ferrules in thiscase being securely clamped in the sockets. Such clamp plates may bemade, if desired, to extend clear across the shoe to take care of theferrules of all cables.

The special advantages of the track construction 'herein set forthresides in the absence of pivot pins, bolts or the like for attachingthe shoes, and the absence of friction between shoes. It also has theadvantage in an easy and quick removal and replacement of any shoewithout dismounting the track. Simply slacken the tension on the cables,remove the locking bolt and unseat the ferrules from the shoe sockets.

The present track for the most part is made of but two different kindsof parts, viz., the traction shoes and cables. The shoes are of novelform in that they are of one piece construction, complete with sockets,flanges, driving and guide lugs. The cables are complete with regularlyspaced ferruled enlargements. The cables automatically space the shoeswhen applied thereto and retain them in place by reason of tension onthe cables. Dismounting of the track is made possible by disconnectionof the cable ends from the anchor shoe. Dismounting of any shoe isreadily done by displacement of the ferrules for that shoe from thechannel sockets.

Tracks of this character may be made for various purposes invariouswidths and lengths and 140 any suitable number of cables employedwithout departing from the spirit of the invention which residesprimarily in the method of and means of providing a positive yetflexible connection between adjacent shoes of the belt and between the145 shoes and cables.

While we have illustrated the various longitudinally extending cables asbeing provided with ferrules for seating in sockets of each shoe of thetrack, it is to be understood that such is 160 nected and the outer onesfree.

connected with a shoe and the other cables be free of a ferruledconnection. Then for the next adjacent shoe the inner cables would becon- In a six cable track, a like arrangement could be employed with twoor four cables attached to each shoe and two passing freely across it.

Having thus described our invention, what we claim as new therein anddesire to secure by Letters-Patent is b 1. A track of the characterdescribed comprising a plurality of cables extending lengthwise of thetrack in parallel relation with ends joined to form a track ofcontinuous belt form, ferrules with rounded ends secured at regularintervals to the cables, traction shoes applied to the cablestransversely thereof having channels across their traction surfaceswithin which the cables are movably contained free of the channel wallsand having sockets with rounded ends formed in the channeled portionspivotally containing the said ferrules.

2. A track of the character described comprising a plurality of cablesextending lengthwise of the track in parallel relation with ends joinedto form a track of continuous belt form, ferrules secured at regularintervals to the cables, traction shoes applied to the cablestransversely thereof having channels across their traction surfaceswithin which the cables are movably contained and having sockets formedin the channeled portions pivotally containing the said ferrules; saidchannels being flared from the sockets toward their outer ends to permitlateral movement of the cables and said sockets having their baseportions arcuately curved to permit rocking of the ferrules thereon.

3. A track of the character described comprising a plurality oflongitudinally extending cables, ferrules fixed to the cables at regularintervals, traction shoes applied to the cables having channels acrosstheir traction faces containing the cables and having pairs of socketscoaxial of the channels removably containing the said ferrules; saidpairs of sockets each having an intermediate entrance common to bothsockets of a pair and through which the ferrules may be unseated bylateral displacement of the cables.

4. A track of the character described comprising a plurality oflongitudinally extended cables in paired relation, ferrules fixedthereon at regular intervals in paired relation, track shoes assembledwith the cables transversely thereof and having channels acrosstheirtraction faces for containing the cables and having alined socketsremovably containing the ferrules'and means removably fixed in the shoesbetween paired ferrules to retain them in their respective sockets.

5. A track of the character described-comprising longitudinallyextending cables arranged in pairs and having ferrules fixedthereon atregular intervals in pairs, traction shoes applied to the cablestransversely thereof and having channels across their traction faces forcontaining the cables and having pairs of sockets in the channeledportions removably containing the ferrules of paired cables; saidsockets each having an entrance laterally offset from the line of thecables, a bolt removably fixed in the shoe between the ferrules ofpaired cables and having a head overlying the ferrules to retain themagainst displacement from their seats.

6. In a track of the character described, in combination, a plurality offlexible cables extending lengthwise of the track, cylindrical ferrulesfixed on the cables at spaced intervals, track shoes having transversechannels opening to the sides and to one face thereof for movablycontaining the cables, and having sockets embodied in the channels tocontain the said ferrules for the attachment of the shoe to the cableand for supporting the cable free of the channel walls; said ferruleshaving their ends curved spherically, and said sockets having endsurfaces vcurved accordingly for pivotal movement of the ferrulesthereon. I

7. In combination, a plurality of parallel, longitudinally extendingcables with ferruled enlargements fixed thereon at regular intervals andtrack shoes formed on their traction surfaces with outwardly opening,transverse channels contalm ing the track cables therein and havingoutwardly opening sockets incorporated in the channels in thelongitudinal, medial lines of the shoes for seating the ferruledenlargements on the cables; said cables having their side and bottomsurfaces curved away from the medial lines of the channels to providefor lateral movement of the cables.

FRANK H. LAMB. GEORGE E. LAMB.

